Also I would remove the graphic card and blow out the slot, clean the contacts and reseat the card.
Just one quick update on my lockup. It's been over 2 weeks now so I am thinking what ever my problem was it seems to have gone away. Have done a kernel update so maybe that was the problem.
I did disassemble my graphics card, clean it up and re-seat it.
I'm now waiting to see if it's still gonna be a problem. In the meantime I have to get some sort of conky going. I am also giving amdcccle another go in case it's a driver related thing.
The graphics card looked dusty, but fairly healthy(no blown caps or scorch marks).
I will continue to investigate this strange phenomenon !
I think this is going to be my last post here seeing it been about 3 weeks + since my last lockup. Everything is really running great now.
I'm now concentrating on getting a respectable conky installed, maybe our paths will cross again.
There may be hardware failure. I also had unusual behavior like yours and finally found my RAM was faulty. After replacing the same I found the problem was solved